The present application claims priority to Italian Patent Application Serial No. MI 2000A 002195, filed Oct. 11, 2000.
The present invention relates to a gluing unit of a tail end of a log.
In order to produce rolls of toilet tissue, kitchen paper and similar, denominated xe2x80x9clogsxe2x80x9d, once the paper has been rolled, the state of the art method is to distribute or position glue in various ways both on a tail end of the individual log and on a portion of the roll of which the log is composed to obtain firm reciprocal binding of the finished log.
In fact, glue is used to join the final end and the remaining part of the winding, which can then be cut into several rolls of the limited dimension required, thus obtaining several finished rolls.
Currently, this deposition of glue is performed either using dispensers to spray the glue or by making the tail end or the roll pass over a slit where glue is dispensed by overflow, once a portion of the tail end has been unwound from the rest of the roll.
These state of the art gluing units, although functioning very well, may not allow glue to be dispensed and distributed evenly and in the exact position desired.
In fact, with the use of dispensers to spray glue, as the glue is distributed by means of the aforesaid dispensers, this distribution is not always continual and straight and glue may also be deposited on parts of the paper where it is not desired or tends to dirty the entire machine. Moreover, it must be considered that the dispensers are complicated and must be checked and adjusted in order not to use too much or, in contrast, too little glue.
When, on the other hand, glue is made to flow from an overflow, over which the tail end of the roll or the roll itself passes, fouling of the entire machine and even the roll may occur, due to the amount of glue and glue that is transported by the paper or spills from the overflow unintentionally.
Moreover, it must be taken into consideration that units to glue a tail end of a log are particularly complicated from the constructional point of view, in general, and from the point of view of interaction between the various parts which feed the log, unwind the tail end, or at least a portion of this, and permit the glue to be positioned on this.
The object of the present invention is therefore to identify a different solution to the technical problem above for correct dispensing or positioning of the glue, solving the problems of prior art related to the entire gluing unit of the tail end of the log.
Another object is to produce a unit capable of performing the job mentioned above that is particularly simple to operate, also in the presence of a high productivity level.
These objects according to the present invention are obtained by producing a gluing unit of a tail end of a log fitted in a load-bearing structure (12) of a machine to produce logs, in which said structure (12) has an inclined surface (13) for feeding logs (14) arriving from a re-reeling machine and in which provided at the end of said inclined surface (13) is a rotating selector (15), equipped with a series of pockets (15a), to retrieve individual logs (14) and feed said logs (14) towards a gluing unit (11), wherein said gluing unit (11) comprises in succession a lower unwinding roller (16) and an upper conveyor belt (17) and, immediately downstream of said unwinding roller (16) a feed roller (18) followed by a suction roller (19), connected to a vacuum source, and a wire (20), and also provided over said unwinding roller (16) and said feed roller (18) with a blowing component (27) to blow a final end (21) of said log (14) and a photocell (28) that interacts to detect said final end (21) of the log (14), wherein said glue dispensing device comprises said wire (20), which is fitted crosswise to the feed direction both of said log (14), and said final end (21), wherein said wire (20) collects glue (26) in a tank (25) while rotating on end pulleys (22).
Further important characteristics and details of `the present invention are set forth in the dependent claims.